17 minutes is good then? I reduced it to 14 without the colouring but still using Simple Sudoku, though the fact I'd already done it may also have been a factor in that. It's towards the top end of times taken when using computer but I usually prefer to use pencil and paper and add candidates as required rather than eliminate them - though I'm becoming more comfortable with the latter!
I've only recently started using colouring and then only when using SS or Sadman. It's certainly not an easy technique for pencil and paper solvers.
Sequence of techniques - on computer with all candidates given I would check for singles, pairs, triplets and locked candidates initially, which is very easy when you can highlight the numbers. Then, probably, x-wings and simple colouring for further eliminations. Check again for singles, pairs, triplets and locked candidates. If simple colouring yields no further eliminations, sometimes it's at that point that I would see if multi-colouring would help. If it does, great - if not look for xy-wings or swordfish. I get stuck if puzzles require forcing chains.
On paper, it's slightly different - I don't think I've ever done a paper puzzle that required anything more difficult than x-wing, including the Sunday Times Superiors, though sometimes I've felt the need to dub a puzzle into a computer program to solve it.
For Times Fiendish or similar difficulty level the sequence is usually: check for singles that can be immediately placed - always at least one of these; enter paired candidates in boxes, rows and columns - depending on the puzzle this will often yield pairs and permit placement of other singles; enter other candidates as required until solution is found. I can usually manage the 'Difficult' level (as per the Times i.e. Pappocom Medium) without pencil marks. I let my daughter do the easy ones!
I won't be going to Lucca - family and work commitments would prevent that but I might be tempted by another Times competition if they do another one